The architectural class of buildings commonly known as "pole buildings" are widely used where clear-span buildings are required for various purposes. Such purposes include riding academies, sports arenas, warehouses, agricultural buildings and the like.
Such structures are of relatively uncomplicated construction. They comprise simply two rows of spaced apart, vertically placed poles disposed in opposite pairs and defining opposite sides of the building. A plurality of roof-supporting truss assemblies of various designs are hoisted to the tops of the poles in side-by-side arrangement and suitably secured in their elevated position. A roof of the desired type and composition then is applied to the truss assemblies and siding of the desired type applied to the outsides of the posts to form the completed structure. This simple, economical, and widely used technique may be used successfully in the erection of buildings having clear spans of 100 feet, or even more.
However, the procedure is attended, by problems. As is evident, where truss assemblies having spans of the order of 100 ft are employed, the great weight of the truss assemblies makes their elevation from ground level to top-of-pole level difficult and hazardous both to equipment and personnel. The truss assemblies conventionally are araised by means of lift trucks, cranes, or hand operated winches attached to the tops of the poles. These procedures are inefficient, expensive, and often damaging to the trusses. They impose a severe limitation on the success of the operation, and in many cases, on the length of clear span which may be achieved by its practice.
It is the general purpose of the present invention to provide an hydraulic winch system which may be used rapidly and effectively in the erection of clear-span, pole-type buildings with safety, economy, and efficiency. By its application, it is possible to elevate each massive truss assembly and secure it in position at the top of the supporting poles in but a few minutes. It also is possible to achieve clear spans not heretofore readily achievable in the construction of buildings of this class.
The foregoing and other objects of the present invention are achieved by means of an hydraulic winch system which, in its broad aspect, comprises an hydraulic circuit including a plurality of rotary, hydraulic-motor-driven winches with suitable controls, and readily portable mounting and attaching means for mounting one of the winches adjacent to each pole. Adjustable cap pieces are removably mounted on the tops of the poles. Support type engaging means, preferably of the stirrup type, are provided at each end of the truss assembly.
Cables mounted on the winches at the bases of the poles are extended upwardly and reeved around the pulleys at the tops of the poles, with the free ends extending downwardly for attachment to the engaging means by which they are releasably engaged with the ends of the truss assemblies.
Depending upon the type and size of the truss assembly, there may be four such winching units employed in the elevation of one truss assembly. Two of the units are employed in conjunction with two poles on one side of the building, and two more employed in conjunction with two other poles at the opposite side of the building. By synchronous operation of the winches, the truss assembly may be elevated to the tops of the poles where it is secured by means of nailing, or otherwise. This sequence is employed successively with a plurality of the truss assemblies until the entire supporting structure of the roof has been completed.